Liquid crystal displays (LCD) have become more and more popular for use in computer monitors or TVs due to light weight, flatness and low radiation. In addition to improving the display quality of LCDs, such as color, contrast and brightness, LCD manufacturers try to improve the manufacturing process to reduce cost and manufacturing time.
Generally, an LCD includes a timing controller, source drivers and at least one gate driver to drive its liquid crystal panel. in a conventional LCD, the timing controller is welded on a control print circuit board, the source drivers are welded on an X-board, and the gate driver is welded on a Y-board. The control print circuit board connects to the X-board via flexible printed circuit boards (FPCs), while the X-board and the Y board each connects to the liquid crystal panel via other FPCs. Therefore, the conventional LCD requires at least three boards connecting to the panel and hence the manufacturing process is complex. In order to simplify the manufacturing process, chip-on-glass (COG) LCDs are developed.
FIG. 1 is diagram of a conventional COG LCD. The COG LCD 100 includes a panel 110, a plurality of source drivers 112, at least one gate driver 114, a printed circuit board 120 and a plurality of flexible printed circuit boards 130. The source drivers 112 and the gate driver 114 are disposed on the glass substrate of the panel 110 and electrically connect to the printed circuit board 120 via the flexible printed circuit boards 130. The timing controller (not shown in FIG. 1) is disposed on the printed circuit board 120, outputting image data and control signals to the source drivers 112 and the gate driver 114. In COG LCD 100, only one board (PCB 120), instead of three, is required to connect to the panel 110 via the FPCs 130. Therefore, the manufacturing process is simplified comparing to that of conventional LCDs not implemented using chip-on-glass technology.
However, the manufacturing process of conventional COG LCDs is still complex because it still needs many flexible printed circuit boards. As shown in FIG. 1, the number of flexible printed circuit board in a conventional COG LCD is 11. In addition, the large number of flexible printed boards in a conventional COG LCD needs a plurality of contact points to connect to the liquid crystal panel. Therefore, the possibility of electrical contact failure increases with the number of contact points.
Accordingly, there is a need for a COG LCD that further reduces the needed number of flexible printed circuit boards.